1. Field of the Invention
The present invention relates to an optical waveguide module comprising at least a ferrule for holding one end of an optical fiber and a waveguide component having an optical waveguide on a substrate made of a material different from that of the ferrule and serving as an optical component. More particularly, the present invention relates to a ferrule capable of obtaining good temperature characteristics and good moist heat characteristics in terms of its relationship with the material of the substrate, an optical waveguide module utilizing this ferrule and an optical component, and a method of manufacturing this optical waveguide module.
2. Description of the Related Art
Along with recent developments in the optical communication techniques, demands have arisen for branching or multiplexing/demultiplexing elements which branch or multiplex light having a predetermined wavelength. Silica glass-based planar optical waveguide circuits (waveguide components) are used to satisfy demands for a higher packing density of these optical components. A planar optical waveguide has a low waveguide loss (a transmission loss accompanying optical branching and the like) and enables low-loss connection with an optical fiber.
As the planar optical waveguide, for example, Japanese Patent Laid-Open No. 58-105111 discloses a buried type silica-based waveguide component obtained by a scheme of forming a glass film in accordance with, e.g., flame hydrolysis (FHD), thereafter forming a circuit pattern in accordance with reactive ion etching (RIE) which is an application of a semiconductor technique, and forming a film of a cladding portion.
When such a waveguide component is to be utilized in an optical component (e.g., an optical waveguide module), input/output optical fibers are generally connected to an optical waveguide formed in this waveguide component. In connecting the waveguide component and the optical fibers, generally, a silica-based ferrule, which is precision-machined and in which optical fibers are fixed is used, as indicated in, e.g., IEEE Photonic Technology Letters, vol. 4, No. 8, (1992), pp. 906-908. The end face of the silica-based ferrule is fixed by adhesion to the end face of the waveguide component by using an ultraviolet-curing adhesive.
For example, Japanese Patent Laid-Open No. 6-51155 discloses a technique for forming a ferrule with silica glass which transmits ultraviolet rays therethrough and solidifying an adhesive between the end faces of the ferrule and waveguide component with each other uniformly within a short period of time, thereby shortening the work time and decreasing the possibility of misalignment between the end faces of the ferrule and waveguide component.